Final answer:
4) Agricultural industry, Propane and natural gas are primarily used in the construction and agricultural industries. Propane is also used in the automotive industry as an alternative fuel. Furthermore, natural gas is vital for generating electricity and for various industrial processes.
Step-by-step explanation:
Propane and natural gas are frequently used in the construction industry and agricultural industry. In the construction industry, they serve as fuel for heating and powering equipment. In agriculture, they are used for heating (such as in greenhouses), powering farm equipment, and even in the production of fertilizer via processes like the Haber process. Propane, in particular, is a versatile fuel and is also employed in areas where natural gas pipelines are not present, due to its portability and ease of storage.
Additionally, propane has applications in the automotive industry as an alternative fuel for vehicles, where it can provide comparable power and acceleration to gasoline with the benefit of higher fuel efficiency and reduced air pollution. It is used in buses, trucks, and police cars among other vehicles.
Natural gas, predominately composed of methane, is a crucial energy source for generating electricity and is also significant for various industrial processes. It's essential in residential settings for cooking and heating, and its by-products such as propane are useful in numerous ways, including for barbeque grills and other home appliances.